/Engine/Source/Editor/UnrealEd/Public/Kismet2/EnumEditorUtils.h
Reorder enumerators in enum. Moves the enumerator at the given initial index to a new target index, shifting other enumerators as needed. E.g. with enum [A, B, C, D, E], moving index 1 to index 3 results in [A, C, D, B, E].
static void MoveEnumeratorInUserDefinedEnum ( class [UUserDefinedEnum](API\Runtime\Engine\Engine\UUserDefinedEnum) * Enum, int32 InitialEnumeratorIndex, int32 TargetIndex )